The number of different designs of powering units has increased enormously in recent decades. The demands placed on powering units have at the same time also increased. Low error rates and a high degree of efficiency are the most important requirements here. A widespread design consists of switching powering units, which are typically smaller and lighter and produce less lost heat than linear powering units. To reduce the switching losses produced in the case of switching powering units and to limit current or voltage peaks, so-called discharge circuits according to the prior art, also known as snubber circuits, are used. Sensitive switching elements are thus protected and the EMC response improved.
Such discharge circuits generally consist of a capacitor as well as a diode and/or an inductor and if necessary a resistor.
In the case of switching powering units developed as full bridge converters, a discharge circuit is used in accordance with the prior art, in order to discharge parasitic voltage peaks, which develop during commutation processes, into the discharge circuit (see FIG. 1). In the case of full bridge converters having a constant input and output voltage, the discharge circuit can be designed according to the prior art such that almost all the energy stored in a capacitor of the discharge circuit is routed to an output capacitor and is thus not lost.